In the manufacture of sterile medical products, in particular filter modules/dialyzers, care must be taken to ensure that the product remains sterile until used on a patient or applied as part of a treatment. For this purpose, it must be ensured that either the sterile barrier is applied to the product itself or that the packaging forms a sterile barrier to the environment which remains intact for the shelf-life time shown on the product, assuming realistic storage conditions.
In terms of their external shape, filter modules/dialyzers are designed solely from the point of the demands of production and application technology. Obviously this shape creates particular demands in terms of the packaging of the filter module/dialyzer. An especially problematic feature of the packaging are the standardized, protruding and sharp-edged connectors on the filter module/dialyzer, as well as edges on the filter module/dialyzer and protection caps on the filter module/dialyzer.
Known packagings for medical products, especially for filter modules/dialyzers, primarily consist of a bag made of plastic or aluminium tube or a seal edge bag (as primary packaging), also a tray made of plastic, cardboard or molded pulp and if necessary an external box (as secondary packaging). The tray in particular generally corresponds to the shape of the product packaged in the primary packaging, resulting in a kind of form fit which aims to achieve positionally stable packaging.
Some medical products, in particular filter modules/dialyzers, have to be sterilized in oxygen-free conditions where applicable. This means that at the time of sterilization, the inside of the primary packaging has to be absolutely oxygen-free. This is normally realized by absorption of the oxygen with a suitable medium, a so-called getter. The medium material can be iron powder or a polymer, for example. The absorber can be added to the primary packaging as a so-called sachet or integrated in the structure of the packaging material (foil).
It is a significant disadvantage that the binding of molecular oxygen in the closed system of the primary packaging results in a volume reduction or negative pressure (in an environment which does not change shape). Known packaging systems are not dimensionally stable, so that after closure of the packaging, their volume is uncontrollably reduced to an extent that corresponds to the oxygen binding. Such a volume reduction of primary packaging allows relative movement to occur between the packaged filter modules/dialyzers inside the secondary packaging as well as between the packaged filter modules/dialyzers and the secondary packaging, wherein this relative movement can in turn result in damage to the sterile barrier.
In known filter module/dialyzer packagings, the above-described problem of relative movement as a result of volume reduction in the case of sterilization and the consequential potential damage to the sterile barrier is countered by the use of appropriately thick foils and/or an oxygen-reduced atmosphere during a packaging process. Both methods disadvantageously incur high material and processing costs. Another disadvantage is that volume reductions cannot be entirely ruled out by providing an oxygen-reduced atmosphere in the packaging process, since in this type of packaging, in particular in a filter module/dialyzer packaging, it is necessary to guarantee an atmosphere which is 100% oxygen-free. As a result, the use of an absorber and the resulting volume reductions are unavoidable. Thicker, mechanically resilient packaging materials for the primary packaging increase the product costs while still failing to provide a 100% guarantee that the sterile barrier will not be damaged.